Re: battle for arnhem....
While the British sought ways of improving the velocity and penetrating power of their 2- and 6-pounder antitank guns, they were also developing a heavier gun intended to stop any tank. In August 1941, a mockup of this new heavy gun -the 17-pounder antitank gun- was unveiled. Without waiting for full-size prototypes to be made, 500 were ordered by the British army.
There was concern that the gun, estimated to weigh 3 tons, would be too unwieldy; however, the gun (and its carriage) ended up weighing just over 2 tons, and moving and setting it up proved imminently manageable. Although there were initially difficulties in matching gun and carriage production, this problem was soon resolved. The 17-pounders were on the North African front in late 1942, just a month before the first Tiger tanks appeared.
There were a few of these guns at Arnhem. Given that tigers and king tigers appeared during the battle, these were very necessary, along with the 6pdr AT gun that was also quite effective against most german tanks at short range due to its APDS ammo.